Insulating glass assemblies for use in the manufacture of windows, doors and the like commonly have two substantially parallel, spaced-apart glass panes spaced apart by a peripheral spacer. Spacers commonly are of metal, usually of tubular configuration, that are formed so as to have two flat, substantially parallel sides facing the confronting surfaces of the panes and bent so as to conform to the periphery of the glass panes. Sealant materials such as polyisobutylene are employed between the flat sides of the spacer and the confronting glass surfaces to seal the glass surfaces to the spacer. To enhance the thermal resistance across the glass assemblies, the interpane space may be filled with an insulating gas such as argon having a thermal conductivity that is less than that of air.
In the manufacture of insulating glass units, uniform production line procedures enable glass assemblies of a single size to be made in large quantities. Custom insulating glass units, on the other hand, are generally manufactured in quantities as small as a single unit, and a single order may require the manufacture of units having varying sizes and shapes.
Various methods and apparatuses have been suggested to enable air within the interpane space to be replaced with an insulating gas such as argon. In one method, the glass panes are adhered to a spacer to form a substantially sealed interpane space, and then air within the space is gradually replaced with argon through an access port. In another method, the interpane space of a multipane glass assembly is filled with an insulating gas by first drawing a vacuum to remove air from the interpane space before both panes are sealed to the spacer, and then charging the evacuated interpane space with an insulating gas. After the interpane space is filled with the insulating gas, the panes are sealed to the spacer.
Various methods and apparatuses for replacing air with an insulating gas in insulating glass units are shown in U.S. Pat. No. 5,017,252, 4,780,164, 5,573,618 (Rueckheim) and 5,476,124 (Lisec). In the last mentioned patent, an apparatus is described in which an insulating glass unit having a pair of glass panes separated by a peripheral spacer is conveyed by a conveyor belt between parallel plates, the bottom edge of the outer glass pane being spaced slightly away from the spacer to provide generally vertical openings along the side edges of the unit. The leading edges of the glass panes are conveyed into contact with a vertical sealing device. Another vertical sealing device is then moved into contact with the trailing edge of the glass panes to seal, with the gas-tight conveyor belt, the space between the glass panes. An insulating gas is then flowed laterally from one vertical sealing device to the other under conditions avoiding turbulence. When the glass unit has been appropriately filled with insulating gas, one plate is advanced toward the other to compress the glass unit between the plates and thus completely adhere the glass panes to the peripheral spacer. This device replaces air with an insulating gas in one glass unit at a time, and due to its employment of non-turbulent gas flow, requires considerable time to replace the air with insulating gas. It would be advantageous to provide a method and apparatus for filling one or a plurality of the same or different size insulating glass units at a time with an insulating gas in a manner providing rapid and substantially complete replacement of air.